Tube for fuses



J. G. CLEMENS.

TUBE FOR FUSES.

APPLICATION FILED oc. 1s, 1920.

Patented Nov. 8, 1921.

w m Y m e a G, n M J lili j just as safe as JOHN G. CLEMENS, OF BUFFALO,NEW YORK.

TUBE FOR FUSES.

Application iiled Gctbei 13, 1920.

To all whom t may concern.

Be it known that l, JOHN G. CLEMENS, a citizen ot the United Sta-tes,residing at Buffalo, in the county of Erie and State oi New York, haveinvented certain new and useful Improvements in Tubes for Fuses, otwhich the following' is a specification.

This invention relates to tubes or casings for electrical fuses and hasfor' its object the provision of an inexpensive tube which will not bedestroyed when the fuse blows and which will provide a safe vent for thegases generated by the blowing of a fuse. lt has been customaryheretofore to construct nonreiillable fuses with powder packed aroundthe fuse element for the purpose ot retarding the escape of theiniiammablc gases generated when the fuse is destroyed, and to providevent holes in the metal end caps or" the fuse. Some reiillable fuseshave been constructed without powder and without vent holes in the endcaps, but this type requires a very strong mechanical construction inorder to withstand the tremendous gas expansion while other types ofrefillable fuses have been provided with vent holes in the end capscovered by metal gauze, but this construction is very expensive. Myinvention, therefore, has for its object the provision of a tube whichcan be adapted to a fuse of any type and which is the originalpowder-packed fuse. With my present invention the cooling substance isnever destroyed nor lost but is retained within the casing or tube whichmay be used indefinitely, the fusible element being renewed from time totime as may be rendered necessary.

My invention is illustrated in the accompanying drawings, in which-`Figure l is a. longitudinal section ot one form of tube embodying myimprovements;

Fig. 2 is a transverse section on the line 2-2 of Fig. l

Fig. 8 is a longitudinal section showing another embodiment of theinvention;

Fig. 4 is a transverse section on the line 4`4 of Fig. 3.

In the form of the invention illustrated in Figs. l and 2, the referencenumeral l indicates a tube of fiber of the usual dimensions. EXtendinglongitudinally of the tube in the wall of the same from the ends thereofinwardly is an annular recess, groove or chamber 2 which terminatesshort of the Speccation of Letters tent.

Patented N ov. 8, 1921. Serial No. 416,704.

center of the tube which is lett solid, as shown at 3. This groove orannular Achamber may be formed in any preferred or convenient manneryand the inner wall thereby produced is shortened so that its end d willbe disposed inwardly from the end 5 of the outer wall. Vents 6 are boredthrough the outer wall to communicate with the chamber 2 at the innerend of the chamber, as clearly shown. The ends ot the tube will beclosed by the usual caps, indicated at 7, which may be iitted upon thetubes in any ot' the methods now generally employed and these caps will,of course, carry the usual electrical connections, while the fusibleelement will be extended between the caps and through the inner bore ofthe tube, as will be readily understood, lVithin the annular chamber 2,I place a. gas-cooling agent which may be some non-combustible powder ormetal gauze rolled into cylindrical form, the gauze, of course, being ofsuch dimensions that its edge will not project beyond the terminal 4 ofthe inner wall and. therefore, will not produce any short circuits norinterfere in any way with the proper i'iow of the current. When powderis used as the cooling agent, iiber washers, indicated in dotted linesat 8, may be fitted across the end of the inner wall ot the tubo andprovided with vent openings to establish an uninterrupted passage iorthe flow of the gases.

Tit will be readily understood from what has been said and uponreference to the drawings that when a fuse blows the gases therebygenerated cannot escape directly to the outer air but will iow throughthe ends of the inner bore of the tube and will be turned back by theend caps 7 and directed into the annular chambers 2, eventually reachingthe vents 6 after flowing through the powder or gauze or other coolingelement. The flow ot the gases to escape from the fuse is thus prolongedso that by the time they reach the vents they are sutliciently cooled toeliminate all liability of damage from lire or other causes. Whilepowder, such as plaster of Paris, may be employed as the cooling agent,metal gauze is preferred inasmuch as the use of retaining washers isthen unnecessary. With my invention there is no necessity for vent holesin the end caps and said caps may, therefore, be produced moreexpeditiously and at less cost than at present and will also bestronger.

My fuse tube or casing may be of any desired outline and the inventionis not restricted to the specific form which has vbeen described asvarious changes may be made without involving any departure from theprinciples of the invention. For instance, in Fig. 3, I have shown thecasing as composed of an outer tube 10 having lateral vent openings 11near its center and adapted to have'the usual caps 12- itted upon itsends. Vithin the vouter tube 10, a second inner tube 13 its fitted andthis inner tube is shorter than the outer tube, as shown. At

the center ofv the inner tube is an annularV rib or flange 111 whichserves to properly space the two tubes and maintain them in concentricrelation and also constitutes a partition between the two series ofvents 11 extending circumferentially around the outerV tube. At the endsof the inner tube are annular ribs or anges 15 which-likewise bearagainst the inner surface of the outer tube and serve as spacers tomaintain the relative positions of the two tubes, and through these endribs or flanges I form longitudinal vents 16 which establish communi!cation betweenVV the Vspaces 17 between the two tubes and thespace 18between the .end of the inner tube and the caps 12. The space 17 will bepacked with a suitable gas-cooling agent and the action of the device,when a fuse blows, will be the same as in the previously described form,the generated gases passing t0 the ends, of the innerV tube and thenturning back through the openings 16 into the annular spaces or'chambers 17` and eventually escaping through the vents 11 in the outertube. Y

A My improved casing is exceedingly simple and inexpensive and will befound highly efiicient when in use for the purpose for which it isdesigned.

Having thus described is claimed as new is:

1. A casing for fuses having a central bore open at its ends andprovided with annular chambers in its end portions, the wall of tiecasing having portions extending beyond the said annular chambers andthe inner bore of the casing to receive end caps whereby to establishcommunication between the said annular chambers and the said bore, andlateral vents leading from said annular chambers to the outer air.

A. double-walled casing for fuses provided with spaced vents through itsouter wall spaced from the ends thereof, and an annular partitionseparatingsaid vents and extending between the inner and outer walls ofthe casing whereby annular chambers Vare provided in the end portions ofthe casing.Y

Y 3. A double-walled casing for electrical fuses having its outer wallextending longithe invention, what Vtudina'lly beyond its inner wall andprovided with vents leading through its outer,l wall from the spacebetween the two walls, and a partition filling the space between thewalls and disposed between the vents through the outer wall wherebyannular chambers are produced in the end portions of the casing betweenthe walls. Y

In testimony whereof I affix my signature.

JOHN G. CLEMENS; [Le] Y

